A review of stem volume and biomass equations for tree species growing in Europe is presented. The mathematical forms of the empirical models, the associated statistical parameters and information about the size of the trees and the country of origin were collated from scientific articles and from technical reports. The total number of the compiled equations for biomass estimation was 607 and for stem volume prediction it was 230. The analysis indicated that most of the biomass equations were developed for aboveground tree components. A relatively small number of equations were developed for southern Europe. Most of the biomass equations were based on a few sampled sites with a very limited number of sampled trees. The volume equations were, in general, based on more representative data covering larger geographical regions. The volume equations were available for major tree species in Europe. The collected information provides a basic tool for estimation of carbon stocks and nutrient balance of forest ecosystems across Europe as well as for validation of theoretical models of biomass allocation.

Carbon sequestration service of Mediterranean forest and other wooded land is threatened by their fragile, complex, and highly evolving nature, due to both human disturbances and climate change. Remote-sensing methods for forest biomass estimation have gained increased attention, and substantial research has been conducted worldwide over the past four decades. Yet, the literature body focused on Mediterranean forests is rather limited as a result of their small extent compared to other biomes. We discuss the remote-sensing studies over the Mediterranean forest and other wooded land, discriminating research based on the primary data source used, such as optical imagery, datasets from active sensors, and combination of multisource data. The review indicates that there is a significant research gap in terms of the studies, as well as a need for a reduction of the errors and uncertainty of estimates, which are associated with both the sensors’ characteristics and the Mediterranean forest and other wooded land structure. Biomass estimates based on optical data were generally less accurate (R² close to 0.70, where R² is the coefficient of determination), however, when data from active sensors were involved, accuracy of estimations was considerably greater (usually R² greater than 0.80). With respect to scale, most of the local scale studies established relationships with R² over 0.70 and as high as 0.98, while the few regional scale studies exhibited R² close to 0.80. Further, in-depth analysis can provide more efficient data fusion, classification methods, and procedures for operational regional and national assessment of forest biomass over such Mediterranean areas.

International audienceAllometric equations describing tree size-shape relationships for beech (Fagus moesiaca Cz.) in the Vermio Mountains of Northern Greece are presented. Diameter at breast height explained most of the variability in the dependent variables (total aboveground, stem, and branch biomass), while tree height was the second most important regressor in estimating foliage mass. Equations developed in USA and Europe for Fagus spp. were also reported and validation with the field data indicated that the American regressions closely predicted total tree biomass for the study forest. In addition, the raw data were used to test a recent theoretical model and large deviations were found between theoretical and empirical values. Finally, generalised equations for Fagus spp. were developed based on these data and several other published equations. Validation of the generalised equations indicated that accurate predictions may be obtained when these regressions are applied over a broad geographical area.Relations concernant la biomasse aérienne pour le hêtre (Fagus moesiaca Cz.), dans le massif du Vermio au nord de la Grèce, et équations génériques pour Fagus sp. Dans l'article suivant sont présentées des équations allométriques décrivant les relations taille-forme pour une espèce particulière de hêtre, Fagus moesiaca (Cz.), dans le massif du Vermio, au nord de la Grèce. Le diamètre à hauteur de poitrine explique en grande partie la variabilité des variables indépendantes (biomasse aérienne totale, biomasse des tiges, biomasse des branches), tandis que la hauteur de l'arbre est la deuxième variable indépendante la plus importante lors de l'estimation de la masse du feuillage. Les équations développées aux états-Unis et en Europe pour les différentes espèces de hêtre (Fagus spp.) sont également présentées. Leur validation, obtenue avec les données recueillies sur le terrain, indique que les régressions américaines prédisent de manière précise la biomasse totale de l'arbre dans la forêt étudiée. En outre, les données de terrain ont été utilisées pour tester un modèle théorique récent, ce qui a permis de mettre en évidence de larges variations entre les valeurs théoriques et empiriques. Finalement, des équations génériques concernant Fagus spp. ont été développées à partir de ces données et de plusieurs autres équations publiées. La validation de ces équations génériques indique que des prédictions précises peuvent être obtenues quand les régressions sont appliquées à une large échelle géographique